1. Field of the Invention
The invention relates to a ligament-tensioning device for activation of the ligament and/or capsule system in the implantation of a joint implant.
2. Description of the Related Art
Other ligament-tensioning devices having a similar function are known. For example, WO 00/78225 A1 discloses a ligament-tensioning device which, in addition to having a prismatic, cylindrical or plate-shaped base body, which has a bearing surface for bearing against a first bone adjoining a non-spherical joint, has right and left tensioning levers having second bearing surfaces which are to be applied to the joint-side surface of a second bone adjoining the joint, the operation of associated handgrips and operating levers being co-ordinated. The opposing portions (bearing surfaces) are supported with respect to one another by four-bar lever mechanisms.
DE 103 48 585 A1 discloses a further ligament-tensioning device which comprises a first, distal bearing plate for bearing against a first skeletal part and a second, proximal bearing plate for bearing against a second skeletal part, the two bearing plates being displaceable relative to one another by a hydraulic drive means and, especially, being tiltable relative to one another by means of a central axis. In addition, they are joined to one another by means of a base body, the distal bearing plate in particular being joined rigidly thereto.
WO 2004/078047 A1 discloses a further ligament-tensioning device, which comprises a distal bearing plate and two proximal bearing plates independently guided and displaceable relative thereto. Guidance is effected therein in each case by means of a double hinge connection and the drive is preferably likewise effected hydraulically.
According to current experiences, the known ligament-tensioning devices still have certain disadvantages in use. Those disadvantages relate especially to the desired exact alignment between the opposing bearing plates and to the expense associated with a hydraulic drive device. In addition, when the known ligament-tensioning devices are used, the joint in question has to be kept open, because substantial parts of the device protrude.